Track tread landing gear with prerotation means



Oct. 14, '1952 o. E. bEVER 2,613,892

TRACK TREAD LANDING GEAR WITH PREIROTATION MEANS Filed Oct. 20, 1949 22 W i BRAKE x 18 J7 3nventor attorney Patented Oct. 14, 1952 r. f

- D I STATES PAT v TRACK TREAD- LANDINGGEAR, WITH PREROTATION I a., E. Dever, Burbank, cam. v Application'fletober 20, 1949, ses me/leases j V f fa Claims. 01. 244 o.)

This invention relates to track tread landing gearwithprerotation means for aircraft.

Landing-gear'of the indicated type is at rest when 'in -th'eair, and is actuated upon engagement with-the ground.-At-the instantof impact the-track tread is'subjected to considerable shock and wear resulting from the sudden rotation imparted" thereto on 1anding.- Such shock and wear are quite a-material factor in a wheel andare a 'considerably greater deleterious factor-in track tread gear, as can be well understood. In addition, when 1 initially engaging the ground; the leadingor oncoming portion of the tread'i's subjected to accumulations of dirt, mud, etc., that pile up in front of the tread and are thereby forced into and through the spaces between the belts that comprise thetread. The

tread gear is quite inefficient because tractive movement-is-instituted only upon landing, often resulting in disruption of the tread and, due to the static inertia thereof, may cause the aircraft to tip over on its nose. Under certain conditions, such as a soft landing terrain, a track tread type of landing gear is preferable to ordinary landing wheels. ,,How ever, because of the difficultieshereinbefore stated; the track tread type of land-'- ing gear has not been found very desirable.

An object of the'present invention is to provide means, in combination with a track tread landing gear, for pre-rotating the tread of said" gear while in the air, to obviate the aforementioned faults in such gear.

The invention also'has for its objects to pro- In the drawings, like reference charactersde ignate' similar parts in the several viewsi Fig. Us a side elevational 'view of atrack tread landing gear to which the presentinventionds/ applied. g 'i' v Fig.2 is an enlarged broken sectionalviewas taken on line 2-2 of Fig.1. I v I 1" With particular reference to "Fig. 1, the land-"- ing'gear comprises a'main arm-'01- frame means 5 that is carried by a strut 6' from the fuselage 1 of an aircraft, and an extensible brace strut 8, in triangular arrangement, connecting strut 6 With-said arm 5, which arm thereby is mounted for pivotal movement relative to strut 6. w One end of arm 5, by means ofa link 9, car-'- ries a grooved" pulley [0. Somewhat similarly, the other end of said arm', by means of a link ll,- carries a similarpulleyl2. A- 'third, smallenpul-a ley l3, through the medium of a link It provided with a pivot l5 intermediate its length, is carried by-arni- 5 between link It and the point of con-'- nection of brace strut 8. A link 16 connects links Hand [4. l Around the three pulleys I0, 12 and 13, is trained a plurality of somewhat elastic belts; l1 that comprise the track of the landing gear. The

centers of said pulleys are on the-apices of a videgsuch means that are'positivein operation,

eonvenientlin' use, easily installedin a working position and easily disconnected therefrom, economicalof manufacture, relatively simple, and of general superiority'and serviceability.

The inventioifalso comprises novel details of construction and novel combinations and. arrangements' of parts,-which will more fully appear inWhie coursegof the following description. However, the drawings merely show and the following description merely describes one embodiment of the present invention, which is given by way of illustration or example only.

inner extension of link 9; I

I lt-iwill'lbe evident'. t at are. "a;

scalene triangle. The belt track has a generally lower horizontal run 18, an angularly and for-- wardly-upwardly' directed run l-9 extending from theforward end of run I8, anda connecting run 20 between pulleys l0 and I? that completes-theendless form of the track. A pair of traction pul-" leys g1, engaged with run 18- of the'track,gis gen-'- era: ..provided, the same being carried cyan When in theair, there are noforces-inabove described landing gearthat act to tauten the track, and said track; therefore,isreasonably slack, and little ro'tative force "applied to a f thepulleyslp, 12 or J3 iszthen needed t tute jrotationbf the. track. v p In the slack tionjo'f the gear, link [4 seeks a *pendent p0 e and... through 11111;, l 6,.draws"1ink,l]l ,a n d pfl [Z-toWardthe right iniFig. 1. When'th'e' gear g o'nthe ground, however, link 'll jfolds on'itspi ['5 iri'a direction topush link; l8 andlthe'la through 11mm, movslpulley '12; in a air to away 'from pulley Ill and thereby taut ns hf trackg- J f v v edci rs' at the .r .-of thetrack w" the.

on the ground.

According to" the invention, either (or both) pulley 10 or 12 is provided with low startingtorque means 22 for institutingrota'tion'of track "while the aircraft is in the air and to thereby eliminate the above-enumerated faultsl In thiscase, wheel [0, which is the trailing wheel of the gear, is equipped with means'iZ so"thattrack runl8 will be pulled in the direction that will cause forward movement; of the aircraft on the ground Inthedrawing, said movement is toward the .left-.; Withoutsuch-torquemeans 22, the-track run B' W0l .11 d be pushed'upon the air craftutouchingthe ground with a consequent tendency of the aircraft to nose over. @Withtmore particular reference to Fig. 2, the link 9 fixedly carries anaxle 23 which, by means of a'suit'able bearing or-bearings 24,; mountspulley, Lflgfor rotation of the latter. A suitable brake,"suggested at 25, interconnects said axle and.v pulley-for controlling the speed of rotation of .the latterjin theusualway for such devices.

..-.The. meansj22 is shown asa low starting torque electric motor thathas afixed annular field 26 carried by a circularfiange 21, fixed by means of akey281to axle 13] and held endwise by a nut 29 against-bearing24,; fIfhe armature 30- of said motor, is;o utward.q ie- .4 26, and is carried by aplate 3| that aflixed by-screws 32 to pulley li0.';-.C, mmutation ,fOr; the, motor 22 is omitted from; the drawing since the same may be designed along: the, lines taught in my Patent No. 2,430,163. Current is brought to the; motor throughsuitable conductors 33 through a hollow arr-1 :23. ii; ,Jj .7 l

Throu h, hem ans spro d, urrent a be broushhto-fieldZB. to energize the same and torotate pulley l and thus rotate belt track ll.

With such pre:rotati o r of thetrack", an aircraft can-.telandeu w ththe track m v n -at a speed,

pulleys, one of whichtrails with respect'to the others during forward flight, endless belt means trained around the pulleys to form a track, frame means for the landing gear adapted to be connected with the strut of anaircraft, linkage interconnecting the frame means with at least one of the pulleys to'move the latter outwardly from the'frame means to tighten the track on-the pulleys when the track engages the ground, and electric motor means embodied Within the trailing pulley forinstituting rotation thereof and of the track before the track engages the ground, said trailing pulley rotating in a direction'to 1 pull onthat portionof the track which engages the ground.

2. In landing gear for aircraft, a plurality of pulleys, one of which trails with respect to the others during forward flight, endless belt means trained around the pulleys to form a track, frame means for the landing gear adapted to be connected' with the strut of anaircraft, linkageinterconnecting the frame means with at least zone; of the pulleys to move the latter relative to the; frame means from a-position in which the tr a clris in a relatively less-stretched condition to a po -j sition in which the track is in a relatively greater stretched condition, and electric motor means embodied within the trailing pulley for institut-- ing, rotation thereof and of the track; while the track is in the relatively less stretched condition, said trailing pulleyrotating in a-direction to pull on that portionof the trackwhich-en gages the ground, the linkage being arranged to move at least one of the pulleys to the-second mentioned position to placethe track in a rela; tively greater stretched condition by engagementv of the track with theground. l y 3. In an aircraft, landing gear havingthree pulleys in scalene-triangular arrangementand having. an, endless track trained around said; three pulleys, ,two of saidgpulleys being i l'I SLIb-F; stantially horizontal-alignment and one of ;-said 1. two pulleys being atfthe rear of the gearand;

pprqsimatins he la d speed t m ve a undueforcestending to disruptthe track. 7, It is immaterialrthat e tr ck is ut d t eini tant n ont st., si ce th mis dy in motion and will provide for a smooth, safe ing that cannot be obtained with an initially ta d-t ac 'Ijheactuatingmeans 22 is notidesigned a have su fiicient horsepower to ariv'e'tne track tread gear" aftergthe track has been tautenedjbut'ohily'suffi de twe to drive the track whe it in the air and'while the track tread gear freely'rotates.

' spiritandscopefof'theinvention. It'is, there fore," not" desired to restrict the invention 'to"th'e particular form of construction illustrated and described, but to cover all modifications which may fall within the scope of the appended claims.

j' thus described my inventiom whatl clainrand desire 'to, secure byi-Letters' Patent is; 1-: landing gear for aircraft, a plurality of trailing with respect to. the others during for wardpflight, that portionv of the track extending; between said two horizontally aligned pulleys be ing substantially horizontal 1 and ,adaptedto e 7 gagethe ground upon ,landing of the aircraft,; the improvement that cgmprises; a low start torque motorembodied in and driving theQmen tioned trailing pulley in a direction to pull 1m said horizontal ground;en gaging portion of .tlfe; track. a

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r I I The following references are of record: filerof this patent: V j

UNITED STATESPATENTS was:

OTHERREEERENC'ES i Key'ser, "Prerotation of lianding Gear Wheels, Aug. 18,1948, 9 pages; pages fi 'and 9 citeda 

